The present invention relates to a packaging apparatus in which plastic films or other sheet materials are put one upon another, and the plastic films so put together are then partially bonded and cut to continuously make bags, and articles to be packaged are charged into these bags.
As shown in FIG. 1, such a conventional apparatus has been so constructed that a sheet material 1' such as plastic film is folded at its center along the longitudinal direction and is put together, for example, by a former 2'. The folded film is then fusion-bonded sideways at given intervals and cut at 3', thereby to continuously make bags 4', and the opening parts of said bag 4' are then manually or mechanically pushed up one by one toward bag-opening blades 5' by a suction means 6' or the like, the bags are conveyed with the bag-opening blades 5' inserted in their opening parts. The blades are separated from each other at a charging position for articles to be packaged, to open the bags, and the articles to be packaged are charged into the bags. Since the thus-made bags of plastic film or the like are difficult to open because of the intimate fitting of their sheets, and since it is difficult to insert the bag-opening blades 5' owing to the difficulty of smoothly performing their opening operation, the conventional apparatus has had defects such as complexity in a mechanism for mechanically effecting a reliable bag-opening operation and blade-inserting operation and further the impossibility of acceleration of these operations.
When a film for making of bags is thin, in particular, it is almost impossible to effect the operation of opening bags and securely putting the blades into them, with various effects such as a requirement of auxiliary installations for preventing the film from being charged with static electricity which makes the opening of bags difficult.